脂肪酸诱导胰岛β细胞凋亡过程中FoxO1对MTP的转录调控研究

Study on Transcriptional Mechanism of FoxO1 Target Gene MTP in Palmitate-induced Pancreatic β Cell Apoptosis

目的研究微粒体甘油三酯转移蛋白MTP在脂肪酸诱导的胰岛B细胞凋亡过程中，转录水平受FoxO1调控的情况。方法脂肪酸处理胰岛8细胞系MIN6细胞，MTF和Hoechst染色检测细胞活力和凋亡情况；ReahimePCR检测MTP相对表达量；染色质免疫共沉淀技术检验FoxO1与肘即启动子区的结合情况；荧光素酶报告基因系统检测Fox01对MTP的转录调控情况。结果脂肪酸处理引起MIN6细胞活力下降、凋亡增加，使MIN6细胞中MTP mRNA水平上升；糖尿病模型小鼠胰岛中MTPmRNA水平上升；转录因子FoxO1的过表达可上调MTP的转录活性；ChIP—PCR结果显示FoxO1能与MZP的启动子区相结合。结论MTP在脂肪酸诱导胰岛B细胞凋亡的过程中，作为转录因子FoxO1的下游靶基因，转录水平受到FoxO1的调控。

Objective To study the transcriptional regulatory mechanism of MTP as FoxO1 target gene in palmitate-induced pancreatic β cells apoptosis. Methods MTT assay and Hoechst staining were used to detect the apoptosis of MIN6 cells. The mRNA level of MTP was examined using Real-time PCR assay. Luciferase reporter assay was used to determine the transcription activity of MTP. ChIP-PCR was performed to confirm the specific FoxO1 binding region of MTP promot- er. Results Palmitate treatment induced MIN6 cells apoptosis. Compared with control, the mRNA level of MTP was significantly elevated in palmitate treated MIN6 cells and primary islets isolated from 4, 8-week db/db mice. Luciferase reporter assay showed that the transcription of MTP was positively regulated by FoxO1. ChIP-PCR confirmed the binding of FoxO1 to the specific region of MTP promoter. Conclusion MTP is positively regulated by transcriptional factor FoxO1 in palmitate-induced pancreatic β cell apoptosis.